The application of ink to paper is more to do with chemistry than calligraphy for the minds that produce printers for Hewlett-Packard Co.
Two of the company’s leading printer experts were in Toronto Wednesday to explain the science
that goes into inkjet and laser printers. HP has just released a brand of inks called Vivera (a combination of the words viva, era and vera) into the market. It’s a rare move for HP to draw attention to such a specific component, said Nils Miller, HP’s Ink/Media senior scientist, but the technology has advanced to such a degree that the company felt it was warranted.
Vivera inks were developed for use for HP’s eight-ink printing systems and on HP’s premium photo paper. Their colours should be resistant to fading for 80 to 100 years based on aging conditions produced in a laboratory.
That HP’s ink, paper and printer are designed to work best with one another is not to lock a consumer into buying HP-only equipment, argued Miller, but is necessary to improve the standards of printer speed and quality.
Miller, who holds a PhD. in chemical engineering, said improvements to printers are being achieved sometimes on the molecular level. “”Twenty years ago, you wouldn’t have said that,”” according to Miller. When the printer industry got going in the 1980s, the innovators were all electrical and mechanical engineers.
A consistent improvement over the years is how the ink is deposited on the page. With thermal inkjet printing, a minute droplet of ink is superheated to more than 300 degrees Celsius. That creates an expanding vapor bubble which forces the ink onto the page. When the bubble collapses, the ink chamber is refilled and the process is repeated. Printers are capable of producing this result on the order of 36,000 vapour bubble cycles per second. The number of nozzles where this process takes place have increased from dozens per inch in the 1980s to more than 600 in HP’s latest inkjet printers.
HP has gone to lengths to produce inks that remain vital and hold their colour after they are ejected from the printer. Miller demonstrated this by squirting a measure of yellow ink into a petrie dish, then adding a droplet of black ink on top. The colours remained separate. When the experiment was produced with a competitor’s ink, the colours almost immediately ran together. The result is a washed-out effect on the page, said Miller.
The inkjet printer is helping drive HP’s digital photography business. In the case of HP’s laserjet line, the technology hasn’t changed radically over the years, according to product support engineer Brett Smith, but price point, ease of use and pages per minute (PPM) all have.
“”We’ve been doing this for 20 years,”” said Smith, “”but not at 55 pages per minute.”” With the earliest lasers, it was less than 10 PPM. Two years ago it was 45.
Inkjet has few moving parts — the superheated ink bubble is what deposits the ink on the page — but laserjet has many, said Smith. It is based on an electrophotographic process of positive and negative electrical charges, which transfers toner particles onto the page. Pages produced by a laser printer may be slightly warm to the touch at first. This is nothing to do with the laser that exposes what’s known as the imaging drum one line at a time — a common misperception, said Smith — but from a fuser that literally melts toner particles onto the paper. Pages from an inkjet aren’t hot because the superheated ink cools exceptionally quickly and is actually room temperature by the time it hits the page.
HP holds hundreds of patents in ink chemistry and more than 9,000 imaging and printing patents. “”This is not a commodity play,”” said Serge Leger, vice-president of supplies channel for HP Canada, “”you need to continue to invest.”” HP pours about $4 billion into R&D annually.
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